Celestial navigation, using hand held marine sextants, has been a primary method of determining a ship's position at sea for several centuries. The hand held sextant, however, has several disadvantages in practical application. As it requires sufficient daylight illumination and weather clarity to see the stars and horizon simultaneously, observation of the altitude of stars is limited to short periods of dawn and twilight. It is difficult to operate the hand held sextant when the ship is rolling, pitching, and yawing due to heavy weather. It is useless when heavy haze or fog obscures the horizon or the stars. Moreover, certain wartime situations require that personnel not be exposed on the bridge or deck thereby rendering sextant observations impossible.